The 2010-2011 La Niña weather event brought lush vegetation to vast semi-arid regions in the Southern Hemisphere and altered the delicate balance of the global carbon sinks. Owen Gaffney explores how La Niña might change in the future and what that might imply.

Earth as a complex system

Earth behaves as a complex system. Complex systems can respond abruptly to changes within the system - these abrupts changes can be highly non-linear. There is strong evidence that the Earth system is prone to such abrupt changes.

Human-induced global change has pushed the Earth system into a no-analogue state — where climatic and other environmental conditions are outside of the range of the last half million years (at least), increasing the likelihood of unpredictable changes with potentially harmful consequences.Exploring and quantifying Earth system interactions is therefore extremely important. The Earth system perspective demands a new scientific approach and innovative conceptual and technical tools. Separate Earth system components, properties and processes — such as the composition and circulation pattern of the atmosphere — still need to be investigated, but should be studied as integral parts of a system, so as to understand their interactions and feedbacks. Furthermore, in the era of global change, humanity must also be considered a part of the Earth system. Indeed, IGBP includes the human social, cultural and economic systems as within the Earth system.

This issue features a special section on carbon. You can read about peak greenhouse-gas emissions in China, the mitigation of black carbon emissions and the effect of the 2010-2011 La Niña event on gl...